When the sleeve of a Porter governor moves downwards, the governor speed
Increases
Decreases
Remain unaffected
First increases and then decreases
Correct Answer :
B. Decreases
Related Questions
A Porter governor is a
Pendulum type governor
Dead weight governor
Spring loaded governor
Inertia governor
Which type of gearing is used in steering system of an automobile?
Rack and pinion
Worm and wheel
Spiral gears
None of the above
For an isochronous Hartnell governor (where r₁ and r₂ = Maximum and minimum radius of rotation of balls respectively, S₁ and S₂ = Maximum and minimum force exerted on the sleeve respectively, and M = Mass on the sleeve)
(m.g + S₁)/(m.g + S₂) = r₁/r₂
(m.g - S₁)/(m.g - S₂) = r₂/r₁
S₁/S₂ = r₁/r₂
S₂/S₁ = r₁/r₂
For an involute gear, the ratio of base circle radius and pitch circle radius is equal to
sinφ
cosφ
secφ
cosecφ
Which of the following disciplines provides study of inertia forces arising from the combined effect of the mass and the motion of the parts?
Theory of machines
Applied mechanics
Mechanisms
Kinetics
A simple spring-mass vibrating system has a natural frequency of fn. If the spring stiffness is halved and the mass is doubled, then the natural frequency will become
fn/2
2 fn
4 fn
8 fn
The cam and follower is an example of
Sliding pair
Rolling pair
Lower pair
Higher pair
The coriolis component of acceleration is taken into account for
Slider crank mechanism
Four bar chain mechanism
Quick return motion mechanism
All of these
A reed type tachometer use the principle of
Longitudinal vibration
Torsional vibration
Transverse vibration
Damped free vibration
In a steam engine, one method of obtaining the earlier cut-off with a simple slide valve is by increasing the angle of advance of the eccentric while the throw of the eccentric, steam lap and exhaust lap are kept constant. This method will
Cause withdrawing or throttling of steam
Reduce length of effective stroke of piston
Reduce maximum opening of port to steam
All of these
The length of a simple pendulum which gives the same frequency as the compound pendulum, is
kG + l₁
kG² + l₁
(kG² + l₁²)/ l₁
(kG + l₁²)/ l₁
Creep in belt drive is due to
Weak material of the belt
Weak material of the pulley
Uneven extensions and contractions of the belt when it passes from tight side to slack side
Expansion of the belt
A Hartnell governor has its controlling force (Fc) given by Fc = ar + b, where r is the radius of rotation and a and b are constants. The governor becomes isochronous when
a is +ve and b = 0
a = 0 and b is +ve
a is +ve and b is -ve
a is +ve and b is also +ve
The ratio of the number of teeth to the pitch circle diameter in millimetres, is called
Circular pitch
Diametral pitch
Module
None of these
In order to facilitate starting of locomotive in any position, the cranks of a locomotive with two cylinders, are placed at
45° to each other
90° to each other
120° to each other
180° to each other
The essential condition of placing the two masses, so that the system becomes dynamically equivalent, is (where l₁ and l₂ = Distance of two masses from the centre of gravity of the body, and kG = Radius of gyration of the body)
l₁ = kG
l₂ = kG
l₁l₂ = kG
l₁l₂ = kG²
The ratio of maximum fluctuation of energy to the workdone per cycle is called
Fluctuation of energy
Maximum fluctuation of energy
Coefficient of fluctuation of energy
None of these
The displacement of the D-slide valve is __________ the steam lap by a distance known as lead of the valve.
Greater than
Less than
Equal to
None of these
The C.G. of a link in any mechanism would experience
No acceleration
Linear acceleration
Angular acceleration
Both angular and linear accelerations
Angle of ascent of cam is defined as the angle
During which the follower returns to its initial position
Of rotation of the cam for a definite displacement of the follower
Through which the cam rotates during the period in which the follower remains in highest position
Moved by the cam from the instant the follower begins to rise, till it reaches its highest position
Consider the following mechanisms:
1. Oscillating cylinder engine mechanism
2. Toggle mechanism
3. Radial cylinder engine mechanism
4. Quick return mechanism Which of the above are inversions of slider crank mechanism?
1, 2 and 4
2, 3 and 4
1, 2 and 3
1, 3 and 4
In order to balance the reciprocating masses,
Primary forces and couples must be balanced
Secondary forces and couples must be balanced
Both (A) and (B)
None of these
The approximate straight line mechanism is a
Four bar linkage
6 bar linkage
8 bar linkage
3 bar linkage
Relationship between the number of links (L) and number of pairs (P) is
P = 2L - 4
P = 2L + 4
P = 2L + 2
P = 2L - 2
In S.H.M., the velocity vector w.r.t. displacement vector
Leads by 90°
Lags by 90°
Leads by 180°
Are in phase
In a reciprocating steam engine, which of the following forms a kinematic link?
Cylinder and piston
Piston rod and connecting rod
Crankshaft and flywheel
Flywheel and engine frame
In a mechanism, usually one link is fixed. If the fixed link is changed in a kinematic chain, then relative motion of other links
Will remain same
Will change
Could change or remain unaltered depending on which link is fixed
Will not occur
The factional torque for square thread at the mean radius r while raising load W is given by
T = W.r tan(φ - α)
T = W.r tan(φ + α)
T = W.r tanα
T = W.r tanφ
A foot step bearing and rotor of a vertical turbine form examples of
Incompletely constrained motion
Partially constrained motion
Completely constrained motion
Successfully constrained motion
The balancing weights are introduced in planes parallel to the plane of rotation of the disturbing mass. To obtain complete dynamic balance, the minimum number of balancing weights to be introduced in different planes is
1
2
3
4